In the past, a treatment for excising a living tissue such as mucosa or the like has been performed by inserting an endoscope into a body and putting a treatment tool into the body through a channel of the endoscope. In this excising treatment, use is made of, e.g., a high-frequency treatment device as disclosed in JP Publication No. 4-329944 (JP4-329944A).
The high-frequency treatment device disclosed in JP4-329944A includes an elongated insertion portion and a front operation portion. The insertion portion is inserted into a body through a channel of an endoscope. The operation portion is connected to a base end of the insertion portion. The insertion portion includes a flexible tube and an operating wire. The operating wire is inserted into the flexible tube in an axially movable manner. A needle-shaped knife portion (an electrode portion) extending in an axial direction is provided in the tip end portion of the operating wire. The operation portion is provided with an operating handle. The operating wire is axially moved by the operation of the operating handle. A high-frequency current can be supplied to the knife portion.
The operating wire is axially moved during the operation of the operating handle. By way of the operating wire, the knife portion is displaced from a storage position in which the knife portion stays within the flexible tube to a use position in which the knife portion protrudes out of the flexible tube. In a state that the knife portion protrudes from the flexible tube into the use position, a high-frequency current is supplied to the knife portion, thereby cauterizing and excising a living tissue with the knife portion.
The high-frequency treatment device as disclosed in JP4-329944A includes a liquid supply means installed in the base end portion of the insertion portion to supply a liquid chemical or the like. The liquid chemical is supplied from the liquid supply means to the tip end of the flexible tube through the flexible tube and can be discharged to the outside from a tip end opening of the flexible tube.
Another high-frequency treatment device includes a bent section formed by bending a tip end of a needle-shaped knife portion (an electrode portion). In this high-frequency treatment device, a living tissue is cauterized and excised while hooking and lifting the living tissue with the bent section of the knife portion.
Another high-frequency treatment device includes a disc-like electrode section arranged at a tip end of a needle-shaped knife portion (an electrode portion). In this high-frequency treatment device, a living tissue is cauterized and excised while hooking and lifting the living tissue with the disc-like electrode section.
If a living tissue is excised through the use of the high-frequency treatment devices referred to above, it is sometimes the case that an incised region bleeds during incision. In this case, the following countermeasures are taken in the respective high-frequency treatment devices.
In case of the high-frequency treatment device disclosed in JP4-329944A, the high-frequency treatment device currently in use is first taken out from a channel of an endoscope. Then, a hemostatic treatment is carried out by inserting a blood-stanching implement into the channel of the endoscope. Once the bleeding is stopped, the blood-stanching implement is replaced by the high-frequency treatment device.
In case of the high-frequency treatment device, the bent section of the tip end of the knife portion or the tip end surface of the disc is pressed against a bleeding point and is supplied with a high-frequency current. As a consequence, blood is coagulated and stanched.
In the event that a large amount of blood is bled from an incised region when a living tissue is incised with a high-frequency treatment device, the bleeding point becomes unclear, making it difficult to perform a hemostatic treatment. In this case, there is a need to wash a bleeding region to clarify the bleeding point. In a high-frequency treatment device having no liquid supply function, however, the treatment device should be first recovered from a channel of an endoscope. Then, a washing solution should be supplied through the channel of the endoscope to wash the bleeding region. Alternatively, a washing liquid should be supplied by replacing a washing catheter arranged within the channel of the endoscope. For that reason, the operation is hard to perform and the time required for high-frequency treatments may possibly become longer.
In case of the high-frequency treatment device of JP4-329944A in which the liquid supply means is arranged in the base end portion of the insertion portion and in which the flexible tube of the insertion portion is opened at the tip end thereof. It is possible to supply a liquid chemical through the flexible tube. However, if the tip end of the flexible tube is opened into a large size, the knife portion is unstably supported and may possibly wobble.
In the high-frequency treatment device having the bent portion or the disc installed at the tip end of the knife portion, if the knife portion is unstably supported, there is likelihood that the bent portion or the disc partially protrudes outward from the outer circumferential surface of the flexible tube when the knife portion is introduced into the flexible tube. The portion protruding outward from the outer circumferential surface of the flexible tube may possibly injure a channel wall when the knife portion is inserted into the endoscope.
According to a technology of JP Patent Application No. 2003-113164 (JP Patent No. 4315725) entitled “high-frequency knife” rod-shaped portion extending in an axial direction of a flexible sheath is installed in an electrode portion. A sliding hole into which the rod-shaped portion is inserted to move forward and backward in the axial direction of the flexible sheath and a liquid supply opening into which the rod-shaped portion cannot be inserted are formed in an insulating chip closing the tip end portion of the flexible sheath.
However, the conventional high-frequency knife is formed into a triangular shape. This poses a problem in that the high-frequency knife has a difficulty in marking a cut region and cannot cleanly scrape out a cut surface.
According to a technology of JP Patent Application No. 2003-146476 UP Publication No. 2005-007161) entitled “EMR treatment implement and EMR device.” a peeling and lifting member is provided in an EMR treatment implement and an EMR device for excising a lesion while alleviating complications and patient's burdens in endoscopic mucosal resection. A target excision portion including a lesion is peeled and separated by the peeling and lifting member. Then, the lesion is lifted up. This helps shorten the time required for operations.
However, the conventional EMR treatment implement and the conventional EMR device are not capable of keeping the lesion in a peeled state during an incising operation. Since the knife is formed into a needle shape, the excision region becomes narrow. This leads to a prolonged operation time. Inasmuch as the tube is not transparent, there is posed a problem in that it is difficult to clearly determine the inward and outward movement of the knife.
According to a technology of JP Patent Application No. 2005-278473 (JP Patent No. 4794564) entitled “treatment implement for endoscopes,” ridge portions and valley portions are formed in the tip end portion and the base end portion of the treatment implement. A plurality of cutters is installed in the valley portions. There is also installed a selector means for selecting one cutter to be used from the plurality of cutters.
In this conventional treatment implement for endoscopes, however, each of the cutters is formed into a shape similar to an irregular elliptical sphere. Therefore, an excision area is unnecessarily increased when excising a lesion. This poses a problem in that the pain felt by a patient is increased and a normal tissue is removed together with a lesion.
According to a technology of JP Patent Application No. 2010-018130 (JP Publication No. 2012-120881) entitled “treatment implement for endoscopes,” a triangular electrode portion includes a first electrode having a triangular chip radially extending from a distal end toward a proximal end.
Since the electrode portion is formed into a triangular shape in this conventional treatment implement for endoscopes, the tube should be laid down when excising a lesion. Another problem lies in that the pointed vertex may make contact with a normal tissue and may injure the normal tissue.
With the conventional technologies referred to above, the lesion is not cleanly cut but is irregularly excised. This poses a problem in that an extended period of time is required for the cut surface to restore after the excising operation.